p62dok has been identified as a substrate of many oncogenic tyrosine kinases such as the chronic myelogenous leukemia (CML) chimeric p210bcr-abl oncoprotein. It is also phosphorylated upon activation of many receptors and cytoplamic tyrosine kinases. However, the biological functions of p62dok in normal cell signaling as well as in p210bcr-abl leukemogenesis are as yet not fully understood. Here we show, in hemopoietic and nonhemopoietic cells derived from p62dok−/− mice, that the loss of p62dok results in increased cell proliferation upon growth factor treatment. Moreover, Ras and mitogen-activated protein kinase (MAPK) activation is markedly sustained in p62dok−/− cells after the removal of growth factor. However, p62dok inactivation does not affect DNA damage and growth factor deprivation–induced apoptosis. Furthermore, p62dok inactivation causes a significant shortening in the latency of the fatal myeloproliferative disease induced by retroviral-mediated transduction of p210bcr-abl in bone marrow cells. These data indicate that p62dok acts as a negative regulator of growth factor–induced cell proliferation, at least in part through downregulating Ras/MAPK signaling pathway, and that p62dok can oppose leukemogenesis by p210bcr-abl.
P62dok, a Negative Regulator of Ras and Mitogen-Activated Protein Kinase (Mapk) Activity, Opposes Leukemogenesis by P210bcr-abl
A. Di Cristofano's present address is Human Genetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111.
Abbreviations used in this paper: BMMC, bone marrow–derived mast cell; CML, chronic myelogenous leukemia; EGF, epidermal growth factor; ES, embryonic stem; KL, kit ligand; MAPK, mitogen-activated protein kinase; PDGF, platelet-derived growth factor; PEF, primary embryonic fibroblast.
Antonio Di Cristofano, Masaru Niki, Mingming Zhao, Fredrick G. Karnell, Bayard Clarkson, Warren S. Pear, Linda Van Aelst, Pier Paolo Pandolfi; P62dok, a Negative Regulator of Ras and Mitogen-Activated Protein Kinase (Mapk) Activity, Opposes Leukemogenesis by P210bcr-abl. J Exp Med 6 August 2001; 194 (3): 275–284. doi: https://doi.org/10.1084/jem.194.3.275
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